package com.xueyu.gateway.util;

import org.springframework.http.HttpHeaders;
import org.springframework.http.server.reactive.ServerHttpRequest;

import java.util.Objects;

/**
 * @author durance
 */
public class RequestUtil {

	public static String getIpAddress(ServerHttpRequest request) {
		String ip = null;

		HttpHeaders headers = request.getHeaders();
		//X-Forwarded-For：Squid 服务代理
		String ipAddresses = headers.getFirst("X-Forwarded-For");

		if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
			//Proxy-Client-IP：apache 服务代理
			ipAddresses = headers.getFirst("Proxy-Client-IP");
		}

		if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
			//WL-Proxy-Client-IP：weblogic 服务代理
			ipAddresses = headers.getFirst("WL-Proxy-Client-IP");
		}

		if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
			//HTTP_CLIENT_IP：有些代理服务器
			ipAddresses = headers.getFirst("HTTP_CLIENT_IP");
		}

		if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
			//X-Real-IP：nginx服务代理
			ipAddresses = headers.getFirst("X-Real-IP");
		}

		//有些网络通过多层代理，那么获取到的ip就会有多个，一般都是通过逗号（,）分割开来，并且第一个ip为客户端的真实IP
		if (ipAddresses != null && ipAddresses.length() != 0) {
			ip = ipAddresses.split(",")[0];
		}

		//还是不能获取到，最后再通过request.getRemoteAddr();获取
		if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
			ip = Objects.requireNonNull(request.getRemoteAddress()).getAddress().getHostAddress();
		}

		//当通过localhost访问服务时，ip会获取为0:0:0:0:0:0:0:1
		if ("0:0:0:0:0:0:0:1".equals(ip)) {
			ip = "127.0.0.1";
		}

		return ip;
	}

}
